1. Field of the Invention
The present invention, which is used in catalytic purification of exhaust gas of an internal combustion engine, relates to an apparatus for mass production of metal substrates and a method of producing metal substrates by continuously inserting pre-made honeycomb bodies into metal outer shells.
2. Description of the Related Art
A xe2x80x9choneycomb bodyxe2x80x9d refers to a thin metal sheet rolled into the shape of a honeycomb, and an xe2x80x9couter shellxe2x80x9d refers to a metal pipe in which a honeycomb body is inserted. A xe2x80x9cmetal substratexe2x80x9d refers to a product in which said honeycomb body has been inserted into the outer shell.
Methods of inserting a honeycomb body into a metal outer shell may be classified into two main types. First is a method of inserting a honeycomb body into a prejoined outer shell in the shape of a pipe as described in Japanese Patent Nos. 5-228376, 6-390, 6-391, 6-47284, 6-63421, 6-182222, 6-238174, 7-24330, 8-206512; and U.S. Pat. No. 5,366,700. Second is a method of inserting a honeycomb body into a nonjoined outer shell in the shape of a xe2x80x9cCxe2x80x9d or into an outer shell of several pieces cut lengthwise, followed later by joining of the outer shell as described in Japanese Patent Nos. 4-122418, 5-220404, 6-269683, 6-277527; and U.S. Pat. No. 5,316,997.
These methods are appropriate for small-lot production of products of various shapes and sizes. However, while mass production of a single product is characteristic of manufacturing industries such as automobiles and motorcycles, these methods are not appropriate for mass production of metal substrates. In particular, when making an outer shell, the process of cutting the sheet into several pieces and changing the same into the shape of a pipe includes no structural part to secure them in a precise position, which in turn leads to a slight movement therein. Consequently, while in the shape of a pipe, the welding machine for welding both side edges into a unit may not precisely align with the welding area, which in turn becomes a cause of defective products.
Further, an additional sizing process is necessary to shape the pipe into a complete cylinder after welding by evening the girth of the pipe, or to shape it into a track shape, if needed, by compress-molding the cylindrical pipe into the track shape. Sizing, as such, is carried out while supporting the pipe cut into a piece, but at the time of sizing, the pipe can move slightly, which leads to a problem of imprecise sizing.
An embodiment herein describes an apparatus for mass production of metal substrates used in purification of exhaust gas, and the method of producing metal substrates using the same, which renders transformed pipes immovable for accurate welding at the welding area in addition to efficiently carrying out the sizing operation.
Another embodiment includes an apparatus for mass production of metal substrates used in purification of exhaust gas, and the method of producing metal substrates using the same, which integrates the following processes into one process for simplifying the multi-step manufacturing process of the prior art: tubing process of an outer shell into the shape of a pipe, inserting process of a honeycomb, and welding process of an outer shell.